Bump version to 0.6

Signed-off-by: Aaron Plattner <aplattner@nvidia.com>

AUTHORS

@@ -2,3 +2,5 @@ Stephen Warren
 Aaron Plattner
 Anssi Hannula
 Kiran Pawar
+James Le Cuirot
+Robert Morell

configure.ac

 AC_PREREQ(2.60)
 
-AC_INIT(libvdpau, 0.5, [vdpau@lists.freedesktop.org], libvdpau)
+AC_INIT(libvdpau, 0.6, [vdpau@lists.freedesktop.org], libvdpau)
 AM_INIT_AUTOMAKE([dist-bzip2 foreign])
 AM_MAINTAINER_MODE